ContentProvider数据共享
1.首先在AndroidManifest.xml文件中添加对外暴露的数据共享接口Content
<provider android:name=".UserProvider" android:authorities="com.yaku.ContentProvider.userprovider"/>
?ContentProvider采用了authorities（主机名/域名）对它进行唯一标识，authorities 就是他的域名
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2.Url解析
content://com.yaku.ContentProvider.userprovider/user/2
【content://】 Android定义的内容提供都的Schema
【com.yaku.ContentProvider.userprovider】? 主机名或者authorities
【user】? 路径
【2】 ID
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示例代码：
数据结构User.java：
package com.yaku.pojo;public class User { private int id; private String name; private int age; public User(int id, String name, int age) { super(); this.id = id; this.name = name; this.age = age; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { return "User [age=" + age + ", id=" + id + ", name=" + name + "]"; }}?
数据库操作DBOpenHelper.java：
package com.yaku.db;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class DBOpenHelper extends SQLiteOpenHelper { private static final String DBNAME = "yaku.db"; //数据库名称 private static final int DBVER = 1;//数据库版本 public DBOpenHelper(Context context) { super(context, DBNAME, null, DBVER); } @Override public void onCreate(SQLiteDatabase db) { String sql = "CREATE TABLE user (userid integer primary key autoincrement, name varchar(20), age integer)"; db.execSQL(sql);//执行有更改的sql语句 } @Override public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) { db.execSQL("DROP TABLE IF EXISTS user"); onCreate(db); }}?
对外共享处理类ContentProviderUser.java：
? 单元测试类（在另一个应用中）：package com.yaku.ContentProvider;import com.yaku.db.DBOpenHelper;import android.content.ContentProvider;import android.content.ContentUris;import android.content.ContentValues;import android.content.UriMatcher;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.net.Uri;public class ContentProviderUser extends ContentProvider { private DBOpenHelper dbOpenHelper; //常量UriMatcher.NO_MATCH表示不匹配任何路径的返回码 private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH); private static final int USERS = 1; private static final int USER = 2; static{ //如果match()方法匹配content://com.yaku.ContentProvider.userprovider/user路径，返回匹配码为1 MATCHER.addURI("com.yaku.ContentProvider.userprovider", "user", USERS); //如果match()方法匹配content://com.yaku.ContentProvider.userprovider/user/123路径，返回匹配码为2 MATCHER.addURI("com.yaku.ContentProvider.userprovider", "user/#", USER);//#号为通配符 } @Override public int delete(Uri uri, String selection, String[] selectionArgs) { SQLiteDatabase db = dbOpenHelper.getWritableDatabase(); int count = 0; switch (MATCHER.match(uri)) { case USERS: count = db.delete("user", selection, selectionArgs); return count; case USER: //ContentUris类用于获取Uri路径后面的ID部分 long id = ContentUris.parseId(uri); String where = "userid = "+ id; if(selection!=null && !"".equals(selection)){ where = selection + " and " + where; } count = db.delete("user", where, selectionArgs); return count; default: throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString()); } } /** * 该方法用于返回当前Url所代表数据的MIME类型。 * 如果操作的数据属于集合类型，那么MIME类型字符串应该以vnd.android.cursor.dir/开头 * 如果要操作的数据属于非集合类型数据，那么MIME类型字符串应该以vnd.android.cursor.item/开头 */ @Override public String getType(Uri uri) { switch (MATCHER.match(uri)) { case USERS: return "vnd.android.cursor.dir/user"; case USER: return "vnd.android.cursor.item/user"; default: throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString()); } } @Override public Uri insert(Uri uri, ContentValues values) { SQLiteDatabase db = dbOpenHelper.getWritableDatabase(); switch (MATCHER.match(uri)) { case USERS: long rowid = db.insert("user", "name", values); Uri insertUri = ContentUris.withAppendedId(uri, rowid);//得到代表新增记录的Uri this.getContext().getContentResolver().notifyChange(uri, null); return insertUri; default: throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString()); } } @Override public boolean onCreate() { this.dbOpenHelper = new DBOpenHelper(this.getContext()); return false; } @Override public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { SQLiteDatabase db = dbOpenHelper.getReadableDatabase(); switch (MATCHER.match(uri)) { case USERS: return db.query("user", projection, selection, selectionArgs, null, null, sortOrder); case USER: long id = ContentUris.parseId(uri); String where = "userid = "+ id; if(selection!=null && !"".equals(selection)){ where = selection + " and " + where; } return db.query("user", projection, where, selectionArgs, null, null, sortOrder); default: throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString()); } } @Override public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { SQLiteDatabase db = dbOpenHelper.getWritableDatabase(); int count = 0; switch (MATCHER.match(uri)) { case USERS: count = db.update("person", values, selection, selectionArgs); return count; case USER: long id = ContentUris.parseId(uri); String where = "userid = "+ id; if(selection!=null && !"".equals(selection)){ where = selection + " and " + where; } count = db.update("user", values, where, selectionArgs); return count; default: throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString()); } }}
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package com.yaku.ContentProvider;import android.content.ContentResolver;import android.content.ContentValues;import android.database.Cursor;import android.net.Uri;import android.test.AndroidTestCase;import android.util.Log;/** * 对ContentProvider工程中的ContentProviderActivity进行单元测试 */public class ContentProviderActivityTest extends AndroidTestCase { private static final String TAG = "ContentProvider"; //往内容提供者添加数据 public void testInsert() throws Throwable{ ContentResolver contentResolver = this.getContext().getContentResolver(); Uri insertUri = Uri.parse("content://com.yaku.ContentProvider.userprovider/user"); ContentValues values = new ContentValues(); values.put("name", "道长"); values.put("age", 86); Uri uri = contentResolver.insert(insertUri, values); Log.i(TAG, uri.toString()); } //更新内容提供者中的数据 public void testUpdate() throws Throwable{ ContentResolver contentResolver = this.getContext().getContentResolver(); Uri updateUri = Uri.parse("content://com.yaku.ContentProvider.userprovider/user/1"); ContentValues values = new ContentValues(); values.put("name", "青眉道长"); contentResolver.update(updateUri, values, null, null); } //从内容提供者中删除数据 public void testDelete() throws Throwable{ ContentResolver contentResolver = this.getContext().getContentResolver(); Uri deleteUri = Uri.parse("content://com.yaku.ContentProvider.userprovider/user/1"); contentResolver.delete(deleteUri, null, null); } //获取内容提供者中的数据 public void testFind() throws Throwable{ ContentResolver contentResolver = this.getContext().getContentResolver(); Uri selectUri = Uri.parse("content://com.yaku.ContentProvider.userprovider/user"); Cursor cursor = contentResolver.query(selectUri, null, null, null, "userid desc"); while(cursor.moveToNext()){ int id = cursor.getInt(cursor.getColumnIndex("userid")); String name = cursor.getString(cursor.getColumnIndex("name")); int age = cursor.getInt(cursor.getColumnIndex("age")); Log.i(TAG, "id="+ id + ",name="+ name+ ",age="+ age); } } }?
监听数据的变化：
package com.yaku.ContentProvider;import android.content.ContentResolver;import android.content.ContentValues;import android.database.Cursor;import android.net.Uri;import android.test.AndroidTestCase;import android.util.Log;/** * 监听数据变化 */public class OtherContentProviderTest extends AndroidTestCase { private static final String TAG = "OtherContentProvider"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Uri insertUri = Uri.parse("content://com.yaku.ContentProvider.userprovider/user"); ContentResolver contentResolver = this.getContentResolver(); //对指定uri进行监听，如果该uri代表的数据发生变化，就会调用PersonObserver中的onChange() contentResolver.registerContentObserver(insertUri, true, new PersonObserver(new Handler())); } private final class PersonObserver extends ContentObserver{ public PersonObserver(Handler handler) { super(handler); } @Override public void onChange(boolean selfChange) { ContentResolver contentResolver = getContentResolver(); Uri selectUri = Uri.parse("content://com.yaku.ContentProvider.userprovider/user"); Cursor cursor = contentResolver.query(selectUri, null, null, null, "userid desc"); while(cursor.moveToNext()){ int id = cursor.getInt(cursor.getColumnIndex("userid")); String name = cursor.getString(cursor.getColumnIndex("name")); int age = cursor.getInt(cursor.getColumnIndex("age")); Log.i(TAG, "id="+ id + ",name="+ name+ ",age="+ age); } } }}?